An artificial diamond (hereinafter referred to as “diamond”) was invented in the 1950s. The diamond, which is known to have the highest hardness out of materials in the earth, has been accordingly used for cutting and grinding tools due to such properties.
Especially, the diamond has been broadly used in a stone processing field where stone such as granite and marble is cut and ground, and in a construction field where a concrete structure is cut and ground.
Typically, a diamond tool comprises segments having diamond particles dispersed therein and a metal core having the segments fixed thereto.
FIG. 1 illustrates an example of a segment type diamond tool.
As shown in FIG. 1, the segment type diamond tool 1 includes a plurality of segments 11 and 12 fixed to a disk-shaped metal core 2, each segment 11, 12 having diamond particles 5 randomly dispersed therein.
In cutting a work piece with the diamond tool, each of the diamond particles dispersed in the cutting segments performs cutting.
However, studies and experiments by the inventors have confirmed that in case where the diamond particles are randomly dispersed in the cutting segments, the diamond particles exhibit a lower cutting rate.
That is because the diamond tool having only cutting segments with the diamond particles randomly dispersed therein experiences inefficiencies as follows. First, grooves formed by the diamond particles of a leading segment may be more widely spaced from each other than the size of the diamond particles, thus unable to completely remove lands between the grooves from a work piece even after the diamond particles of a trailing segment pass along the lands. Second, the diamond particles of a trailing segment may pass along the grooves previously formed by the diamond particles of a leading segment so that the diamond particles of the trailing segment do not perform any work.
The segments having the diamond particles randomly dispersed are fabricated via powder metallurgy in which the diamond particles are mixed with metal powder, molded and then sintered.
In case of fabricating the cutting segments by powder metallurgy, the diamond particles are not evenly dispersed owing to differences in particle sizes and specific gravities in mixing, molding and sintering fine diamond particles together with metal powders. Thus as shown in FIG. 1, this disadvantageously leads to a cutting surface 3 having too many diamond particles or a cutting face 4 having too few diamond particles, causing the diamond particles to segregate.
The diamond particles segregated as described above disadvantageously lead to decline in cutting rate of the cutting tool and also useful life thereof.
To overcome such problems of the conventional technique, the inventors have carried out studies and experiments, and based on the results thereof, invented a diamond tool capable of enhancing cutting rate and reducing the amount of fine debris generated during cutting by properly arranging diamond particles in cutting segments of the diamond tool. The diamond tools of such invention are disclosed in Korean Patent Application No. 2001-60680 and No. 2003-55532.